The qalter utility allows users to change the attributes of a
batch job.
As a means of altering a queued job, the qalter utility is
superior to deleting and requeuing the batch job insofar as an
altered job retains its place in the queue with some traditional
selection algorithms. In addition, the qalter utility is both
shorter and simpler than a sequence of qdel and qsub utilities.
The result of an attempt on the part of a user to alter a batch
job in a RUNNING state is implementation-defined because a batch
job in the RUNNING state will already have opened its output
files and otherwise performed any actions indicated by the
options in effect at the time the batch job began execution.
The options processed by the qalter utility are identical to
those of the qsub utility, with a few exceptions: -V, -v, and -q.
The -V and -v are inappropriate for the qalter utility, since
they capture potentially transient environment information from
the submitting process. The -q option would specify a new queue,
which would largely negate the previously stated advantage of
using qalter; furthermore, the qmove utility provides a superior
means of moving jobs.
Each of the following paragraphs provides the rationale for a
qalter option.
Additional rationale concerning these options can be found in the
rationale for the qsub utility.
The -a option allows users to alter the date and time at which a
batch job becomes eligible to run.
The -A option allows users to change the account that will be
charged for the resources consumed by the batch job. Support for
the -A option is mandatory for conforming implementations of
qalter, even though support of accounting is optional for
servers. Whether or not to support accounting is left to the
implementor of the server, but mandatory support of the -A option
assures users of a consistent interface and allows them to
control accounting on servers that support accounting.
The -c option allows users to alter the checkpointing interval of
a batch job. A checkpointing system, which is not defined by
POSIX.1‐2008, allows recovery of a batch job at the most recent
checkpoint in the event of a crash. Checkpointing is typically
used for jobs that consume expensive computing time or must meet
a critical schedule. Users should be allowed to make the tradeoff
between the overhead of checkpointing and the risk to the timely
completion of the batch job; therefore, this volume of
POSIX.1‐2017 provides the checkpointing interval option. Support
for checkpointing is optional for servers.
The -e option allows users to alter the name and location of the
standard error stream written by a batch job. However, the path
of the standard error stream is meaningless if the value of the
Join_Path attribute of the batch job is TRUE.
The -h option allows users to set the hold type in the Hold_Types
attribute of a batch job. The qhold and qrls utilities add or
remove hold types to the Hold_Types attribute, respectively. The
-h option has been modified to allow for implementation-defined
hold types.
The -j option allows users to alter the decision to join (merge)
the standard error stream of the batch job with the standard
output stream of the batch job.
The -l option allows users to change the resource limits imposed
on a batch job.
The -m option allows users to modify the list of points in the
life of a batch job at which the designated users will receive
mail notification.
The -M option allows users to alter the list of users who will
receive notification about events in the life of a batch job.
The -N option allows users to change the name of a batch job.
The -o option allows users to alter the name and path to which
the standard output stream of the batch job will be written.
The -P option allows users to modify the priority of a batch job.
Support for priority is optional for batch servers.
The -r option allows users to alter the rerunability status of a
batch job.
The -S option allows users to change the name and location of the
shell image that will be invoked to interpret the script of the
batch job. This option has been modified to allow a list of shell
name and locations associated with different hosts.
The -u option allows users to change the user identifier under
which the batch job will execute.
The job_identifier operand syntax is provided so that the user
can differentiate between the originating and destination (or
executing) batch server. These may or may not be the same. The
.server_name portion identifies the originating batch server,
while the @server portion identifies the destination batch
server.
Historically, the qalter utility has been a component of the
Network Queuing System (NQS), the existing practice from which
this utility has been derived.
